/* This source file is part of the ATMEL AVR32-UC3-SoftwareFramework-1.6.0 Release */

/*This file is prepared for Doxygen automatic documentation generation.*/
/*! \file *********************************************************************
 *
 * \brief WDT driver for AVR32 UC3.
 *
 * This file contains definitions and services for the AVR32 WatchDog Timer.
 *
 * - Compiler:           IAR EWAVR32 and GNU GCC for AVR32
 * - Supported devices:  All AVR32 devices with a WDT module can be used.
 * - AppNote:
 *
 * \author               Atmel Corporation: http://www.atmel.com \n
 *                       Support and FAQ: http://support.atmel.no/
 *
 ******************************************************************************/

/* Copyright (c) 2009 Atmel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. The name of Atmel may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * 4. This software may only be redistributed and used in connection with an Atmel
 * AVR product.
 *
 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
 *
 */

#include <avr32/io.h>
#include "compiler.h"

/*! \brief Sets the WatchDog Timer Control register to the \a ctrl value thanks
 *         to the WatchDog Timer key.
 *
 * \param ctrl  Value to set the WatchDog Timer Control register to.
 *
 * \note The KEY bit-field of \a ctrl is assumed to be zero.
 */
static void wdt_set_ctrl(unsigned long ctrl)
{
  AVR32_WDT.ctrl = ctrl | (AVR32_WDT_KEY_VALUE << AVR32_WDT_CTRL_KEY_OFFSET);
  AVR32_WDT.ctrl = ctrl | ((unsigned long) (~AVR32_WDT_KEY_VALUE << AVR32_WDT_CTRL_KEY_OFFSET) & AVR32_WDT_CTRL_KEY_MASK);
}


long long wdt_get_us_timeout_period(void)
{
  // Read CTRL.PSEL and translate it into us.
  return (AVR32_WDT.ctrl & AVR32_WDT_CTRL_EN_MASK) ?
           ((1ULL << (((AVR32_WDT.ctrl & AVR32_WDT_CTRL_PSEL_MASK) >> AVR32_WDT_CTRL_PSEL_OFFSET) + 1)) *
            1000000 + AVR32_PM_RCOSC_FREQUENCY / 2) / AVR32_PM_RCOSC_FREQUENCY :
            -1ULL;
}


void wdt_disable(void)
{
  wdt_set_ctrl(AVR32_WDT.ctrl & ~AVR32_WDT_CTRL_EN_MASK);
}


unsigned long long wdt_enable(unsigned long long us_timeout_period)
{
#define MIN_US_TIMEOUT_PERIOD   (((1ULL <<  1                             ) * 1000000 + AVR32_PM_RCOSC_FREQUENCY / 2) / AVR32_PM_RCOSC_FREQUENCY)
#define MAX_US_TIMEOUT_PERIOD   (((1ULL << (1 << AVR32_WDT_CTRL_PSEL_SIZE)) * 1000000 + AVR32_PM_RCOSC_FREQUENCY / 2) / AVR32_PM_RCOSC_FREQUENCY)

  // Set the CTRL.EN bit and translate the us timeout to fit in CTRL.PSEL using
  // the formula Twdt = 2pow(PSEL+1) / fRCosc
  wdt_set_ctrl(AVR32_WDT_CTRL_EN_MASK |
               ((32 - clz(((((Min(Max(us_timeout_period, MIN_US_TIMEOUT_PERIOD), MAX_US_TIMEOUT_PERIOD) *
                              AVR32_PM_RCOSC_FREQUENCY + 500000) / 1000000) << 1) - 1) >> 1) - 1) <<
                AVR32_WDT_CTRL_PSEL_OFFSET));

  // Return the actual wdt period in us.
  return wdt_get_us_timeout_period();
}


void wdt_reenable(void)
{
  wdt_set_ctrl(AVR32_WDT.ctrl | AVR32_WDT_CTRL_EN_MASK);
}


void wdt_clear(void)
{
  AVR32_WDT.clr = 0;
}


void wdt_reset_mcu(void)
{
  Disable_global_interrupt();
  // Enable the WDT with a 0s period (fastest way to get a Watchdog reset).
  wdt_enable(0);
  while (1);
}
